Huge bandwidth usage on Firefox (7Mbps!)

Hello all,

We have a bandwidth problem on our Jitsi deployment (latest stable) when using firefox.

On a conference of 4 participants (all of them using 480p resolution), Jitsi uses 7Mbps UP and DOWN. Is that normal ?

Firefox 60.2.2 :
image

This behavior doesn’t happen with Chrome.
Chrome :
image

thanks.

Firefox doesn’t support simulcast chrome does that’s why… I mean if I am not mistaken

But 7Mbps for 480p is too much, isn’t it ?

1,555Kbps (480p stream) x4 = 6,222Kbps

  • SD quality video is standard 480p video. SD-quality video uses about 0.7GB (700MB) per hour.

700 Megabytes/s divided by / 60 seconds / 60 minutes = 194Kilobytes per second
(Converting from Megabytes/s to Megabits/s we multiply by 8): 194 KBps * 8 = 1,555Kilobits/s

1,555 * 4 = 6,222Kbps <-- This number does seem high, but is within the realm of possibility.

Is this right?
Is firefox sending 4x 480p video streams to 4 recipients, each totaling 1,555 Kbps

Firefox sends one 480p video stream only and receives 3.
In this case, Firefox should use 1.555 Kbps only in upload and 3*1.555=4.665 Kbps in download.
I believe something is wrong with bandwidth usage when using Firefox

Have you check, it can be just a problem the client reading the stats?

Well it’s definitely a display bug on Firefox 62.0.2 ESR. It shows incorrect values as below :

image

image

I ran wireshark and figured out that that I only use 1496 Kbps for upload and 4011 Kbps for download
image

Thanks for confirming, so the bug should be inside this method https://github.com/jitsi/lib-jitsi-meet/blob/070c67bf5dad7092b29d99604f4d1f2a363159c3/modules/statistics/RTPStatsCollector.js#L1079 I had added that, but I do not have time at the moment to debug and fix it, sorry.
You can create an issue lib-jitsi-meet repo with your findings and put a link to this thread, thanks. Not it will fix it itself that way :), but just to have it written.

Done. https://github.com/jitsi/lib-jitsi-meet/issues/965
Thanks @damencho

This doesn’t seem right. Can you check if firefox is actually sending
7Mbps? It could be a bug in the stats in the UI.

Boris